Cosc 2150:
Computer Organization
Chapter 1:
Introduction, History, and Performance
Overview
•
Why study computer organization and
architecture?
—Design better programs, including system software
such as compilers, operating systems, and device
drivers.
—Optimize program behavior.
—Evaluate (benchmark) computer system
performance.
—Understand time, space, and price tradeoffs.
Overview (2)
• Computer organization
—Encompasses all physical aspects of computer
systems.
—E.g., circuit design, control signals, memory types.
– How does a computer work?
• Computer architecture
—Logical aspects of system implementation as seen by
the programmer.
—E.g., instruction sets, instruction formats, data types,
addressing modes.
– How do I design a computer?
Computer Components
• There is no clear distinction between matters
related to computer organization and matters
relevant to computer architecture.
• Principle of Equivalence of Hardware and
Software:
—Any task done by software can also be done using
hardware, and any operation performed directly by
hardware can be done using software.
+ Assuming speed is not a concern
Computer Components (2)
• At the most basic level, a computer is a device
consisting of three pieces:
—A processor to interpret and execute programs
—A memory to store both data and programs
—A mechanism for transferring data to and from the
outside world.
An Example System
Consider this advertisement:
What does it all mean??
Measurements
Measures of capacity and speed:
•
•
•
•
•
•
•
•
Kilo- (K) = 1 thousand = 103 and 210
Mega- (M) = 1 million = 106 and 220
Giga- (G) = 1 billion = 109 and 230
Tera- (T) = 1 trillion = 1012 and 240
Peta- (P) = 1 quadrillion = 1015 and 250
Exa- (E) = 1 quintillion = 1018 and 260
Zetta- (Z) = 1 sextillion = 1021 and 270
Yotta- (Y) = 1 septillion = 1024 and 280
Whether a metric refers to a power of ten or a power of
two typically depends upon what is being measured.
Measurements (2)
• Hertz = clock cycles per second (frequency)
—1MHz = 1,000,000Hz
—Processor speeds are measured in MHz or GHz.
• Byte = a unit of storage
—1KB = 210 = 1024 Bytes
—1MB = 220 = 1,048,576 Bytes
—1GB = 230 = 1,099,511,627,776 Bytes
—Main memory (RAM) is measured in GB
—Disk storage is measured in GB for small systems, TB
(240) for large systems.
Measurements (3)
• Measures of time and space:
—Milli- (m) = 1 thousandth = 10-3
—Micro- () = 1 millionth = 10-6
—Nano- (n) = 1 billionth = 10-9
—Pico- (p) = 1 trillionth = 10-12
—Femto- (f) = 1 quadrillionth = 10-15
—Atto- (a) = 1 quintillionth = 10-18
—Zepto- (z) = 1 sextillionth = 10-21
—Yocto- (y) = 1 septillionth = 10-24
Measurements (4)
• Millisecond = 1 thousandth of a second
—Hard disk drive access times are often 10 to 20
milliseconds.
• Nanosecond = 1 billionth of a second
—Main memory access times are often 50 to 70
nanoseconds.
• Micron (micrometer) = 1 millionth of a meter
—Circuits on computer chips are measured in microns.
An Example System
• We note that cycle time is the reciprocal of clock
frequency.
• A bus operating at 133MHz has a cycle time of
7.52 nanoseconds:
133,000,000 cycles/second = 7.52ns/cycle
Now back to the advertisement ...
An Example System (2)
The microprocessor is the
“brain” of the system. It
executes program instructions.
This one is a Pentium (Intel)
running at 3.06GHz.
An Example System (3)
• Computers with large main memory capacity
can run larger programs with greater speed
than computers having small memories.
• RAM is an acronym for random access memory.
Random access means that memory contents
can be accessed directly if you know its location.
• Cache is a type of temporary memory that can
be accessed faster than RAM.
An Example System (4)
This system has 4GB of (fast)
synchronous dynamic RAM
(SDRAM) . . .
… and two levels of cache memory, the level 1 (L1)
cache is smaller and (probably) faster than the L2 cache.
Note that these cache sizes are measured in KB and MB.
An Example System (5)
Hard disk capacity determines
the amount of data and size of
programs you can store.
This one can store 500GB. 7200 RPM is the
rotational speed of the disk. Generally, the faster a
disk rotates, the faster it can deliver data to RAM.
(There are many other factors involved.)
An Example System (6)
ATA stands for advanced technology attachment, which
describes how the hard disk interfaces with (or
connects to) other system components.
A DVD can store about
4.7GB of data. This drive
supports rewritable
DVDs, +/-RW, that can be
written to many times..
16x describes its speed.
An Example System (7)
Ports allow movement of data
between a system and its external
devices.
This system has
ten ports.
An Example System (8)
• Serial ports send data as a series of pulses
along one or two data lines.
• Parallel ports send data as a single pulse along
at least eight data lines.
• USB, Universal Serial Bus, is an intelligent serial
interface that is self-configuring. (It supports
“plug and play.”)
An Example System (9)
System buses can be augmented by
dedicated I/O buses. PCI, peripheral
component interface, is one such bus.
This system has two PCI
devices: a video card and a
sound card.
An Example System (10)
The number of times per second that the image on a
monitor is repainted is its refresh rate. The dot pitch
of a monitor tells us how clear the image is.
This one has a dot pitch of
0.24mm and a refresh rate
of 75Hz.
The video card contains memory
and programs that support the
monitor.
An Example System (11)
•
Throughout the remainder of the course you
will see how these components work and how
they interact with software to make complete
computer systems.
This statement raises two important questions:
What assurance do we have that computer
components will operate as we expect?
And what assurance do we have that
computer components will operate together?
Standards Organizations
• There are many organizations that set computer
hardware standards
—to include the interoperability of computer
components.
• Throughout your career, you will encounter
many of them.
• Some of the most important standards-setting
groups are . . .
Standards Organizations (2)
• The Institute of Electrical and Electronic
Engineers (IEEE)
—Promotes the interests of the worldwide electrical
engineering community.
—Establishes standards for computer components, data
representation, and signaling protocols, among many
other things.
Standards Organizations (3)
• The International Telecommunications Union
(ITU)
—Concerns itself with the interoperability of
telecommunications systems, including data
communications and telephony.
• National groups establish standards within their
respective countries:
—The American National Standards Institute (ANSI)
—The British Standards Institution (BSI)
Standards Organizations (4)
• The International Organization for
Standardization (ISO)
—Establishes worldwide standards for everything from
screw threads to photographic film.
—Is influential in formulating standards for computer
hardware and software, including their methods of
manufacture.
Note: Iso is not an acronym. Iso comes from the Greek,
isos, meaning “equal.”
HISTORY
Historical Development
• To fully appreciate the computers of today, it is
helpful to understand how things got the way
they are.
• The evolution of computing machinery has
taken place over several centuries.
• In modern times computer evolution is usually
classified into four generations according to the
salient technology of the era.
We note that some of the following dates are approximate
and this is not a complete list.
“Calculators”
• Abacus
— Was used as early as 2400BC in Babylon
• Slide Rule
—William Oughtred, 1625
• There were varying “calculators” through out
history.
• There are having been many “robots” in early
history as well
—Dating back to ancient Egypt
—Leonardo da Vinci created a self propelled mechanical
lion that could be programmed to walk around.
– Presented to King Francis I of France in 1515.
Mechanical Era (1600s-1940s)
• Wilhelm Schickhard, 1623
— Automatically add, subtract, multiply and divide
— Up to six digits, base 10 machine.
• Blaise Pascal, 1642
— Mass produced first working machine (about 50 of them)
— could only add and subtract, up 8 digits
• Gottfired Liebniz, 1672
— Improved Pascal’s machine
— add, subtract, multiply and divide
— Leibniz once said "It is unworthy of excellent men to lose hours
like slaves in the labor of calculation which could safely be
relegated to anyone else if machines were used.”
— Also the co-inventor of calculus
• Charles Babbage, 1822 or 34 and Ada Lovelace
—Considered the father of modern Computer
—wanted better accuracy in calculations
—Used a Difference Engine and a Analytic engine
– Could perform any math operation
– Used punch card
—Used the modern structure, I/O, storage, ALU
—The machine would do an addition in 3 seconds and
a multiplication or division in 2-4 minutes.
• George Boole, 1847
— Mathematical of laws of logic
• Herman Hollerith, 1889
— Used modern day punch card
— Formed Tabulating Machine Computer (now called IBM)
— Used his machine for the Census
– Estimated 7.5 years by hand for the 1890 census
– His machine figured it in 2 months
• Konrad Zuse, 1938
— Built the Z1, the first binary machine.
—A reproduction of Z1 in Technik Museum in Berlin
• Howard Aiken, 1943
— Designed the Mark I, based of Baggage’s machine
• Summary:
— Designed to reduce time of calculations and increase accuracy
— Problems:
– Used gears and pulleys, prone to mechanical failures
– Cumbersome and expensive
– Worst: Unreliable
The Electronic Era
• Generation 1: Vacuum Tube(1945 – 1958)
• ENIAC - background
—Electronic Numerical Integrator And Computer
—Eckert and Mauchly
—University of Pennsylvania
—Trajectory tables for weapons
—Started 1943
—Finished 1946
– Too late for war effort
—Used until 1955
ENIAC - details
•
•
•
•
•
•
•
•
Decimal (not binary)
20 accumulators of 10 digits
Programmed manually by switches
18,000 vacuum tubes, 10K capacitors, 6K
switches, 70K resistors
30 tons
15,000 square feet (30 x 50 feet)
140 kW power consumption
5,000 additions per second
von Neumann/Turing
•
•
•
•
Stored Program concept
Storing programs and data in main memory
ALU operating on binary data
Control unit interpreting instructions from
memory and executing
• Input and output equipment operated by control
unit
• Princeton Institute for Advanced Studies
—IAS
• Completed 1952
• Basis for virtually all computers designed since
then
• Major features
—Data and instructions (programs) are stored in readwrite memory
—Memory contents are addressable by location
regardless of where it is located at.
—Sequential execution!
—Stored-program concept
Fetch execute cycle
• In it’s simplest form
—Read in an instruction
—Execute the instruction
—Repeat
• We will add to this cycle through out the
semster
• Von Nueman machine has 21 instructions
—Loads, stores, condition/unconditional branches
(jumps), arithmetic, and address modify
Structure of von Neumann machine
IAS - details
• 1000 x 40 bit words
—Binary number
—2 x 20 bit instructions
• Set of registers (storage in CPU)
—Memory Buffer Register
—Memory Address Register
—Instruction Register
—Instruction Buffer Register
—Program Counter
—Accumulator
—Multiplier Quotient
Structure of IAS –
detail
1944 Harvard Mark I
• the Harvard Mark-1 was a
room-sized, relay-based
calculator. The machine had a
fifty-foot long camshaft that
synchronized the machine’s
thousands of component
parts. The Mark-1 was used to
produce mathematical tables
but was soon superseded by
stored program computers.
• Created by Howard
Aiken and Grace
Hopper
Commercial Computers
•
•
•
•
•
1947 - Eckert-Mauchly Computer Corporation
UNIVAC I (Universal Automatic Computer)
US Bureau of Census 1950 calculations
Became part of Sperry-Rand Corporation
Late 1950s - UNIVAC II
—Faster
—More memory
IBM
• Punched-card processing equipment
• 1953 - the 701
—IBM’s first stored program computer
—Scientific calculations
• 1955 - the 702
—Business applications
• Lead to 700/7000 series
Transistors
•
•
•
•
•
•
•
•
Replaced vacuum tubes
Smaller
Cheaper
Less heat dissipation
Solid State device
Made from Silicon (Sand)
Invented 1947 at Bell Labs
William Shockley et al.
Transistor Based Computers
•
•
•
•
•
•
Second generation machines
High level languages introduced
Floating point arithmetic
NCR & RCA produced small transistor machines
IBM 7000
DEC - 1957
—Produced PDP-1
Microelectronics
• Literally - “small electronics”
• A computer is made up of gates, memory cells
and interconnections
• These can be manufactured on a semiconductor
• e.g. silicon wafer
Generations of Computer
• Vacuum tube - 1946-1957
• Transistor - 1958-1964
• Small scale integration - 1965 on
—Up to 100 devices on a chip
• Medium scale integration - to 1971
—100-3,000 devices on a chip
• Large scale integration - 1971-1977
—3,000 - 100,000 devices on a chip
• Very large scale integration - 1978 to date
—100,000 - 100,000,000 devices on a chip
• Ultra large scale integration
—Over 100,000,000 devices on a chip
Moore’s Law (1965)
•
•
•
•
Increased density of components on chip
Gordon Moore - cofounder of Intel
Number of transistors on a chip will double every year
Since 1970’s development has slowed a little
— Number of transistors doubles every 18 months
• Cost of a chip has remained almost unchanged
• Higher packing density means shorter electrical paths,
giving higher performance
• Smaller size gives increased flexibility
• Reduced power and cooling requirements
• Fewer interconnections increases reliability
Rock’s Law
• Rock’s Law
—Arthur Rock, Intel financier
—“The cost of capital equipment to build
semiconductors will double every four years.”
—In 1968, a new chip plant cost about $12,000.
• As a Note:
— At the time, $12,000 would buy a nice home in the suburbs.
— An executive earning $12,000 per year was “making a very comfortable
living.”
Rock’s Law (2)
• Rock’s Law
—In 2010, a chip plants under construction cost well
over $4 billion.
$4 billion is more than the gross domestic
product of some small countries, including
Barbados, Mauritania, and Rwanda.
—For Moore’s Law to hold, Rock’s Law must fall, or
vice versa. But no one can say which will give out
first.
IBM 360 series
• 1964
• Replaced (& not compatible with) 7000 series
• First planned “family” of computers
—Similar or identical instruction sets
—Similar or identical O/S
—Increasing speed
—Increasing number of I/O ports (i.e. more terminals)
—Increased memory size
—Increased cost
• Multiplexed switch structure
DEC PDP-8
•
•
•
•
•
1964
First minicomputer (after miniskirt!)
Did not need air conditioned room
Small enough to sit on a lab bench
$16,000
—$100k+ for IBM 360
• Embedded applications & OEM
• BUS STRUCTURE
DEC - PDP-8 Bus Structure
Semiconductor Memory
• 1970
• Fairchild
• Size of a single core
—i.e. 1 bit of magnetic core storage
•
•
•
•
Holds 256 bits
Non-destructive read
Much faster than core
Capacity approximately doubles each year
Intel
• 1971 - 4004
—First microprocessor
—All CPU components on a single chip
—4 bit
• Followed in 1972 by 8008
—8 bit
—Not the successor to 4004, independently designed.
—Both designed for specific applications
• 1974 - 8080
—Intel’s first general purpose microprocessor
Pentium Evolution (1)
• 8080
— first general purpose microprocessor
— 8 bit data path
— Used in first personal computer – Altair
• 8086
— much more powerful
— 16 bit
— instruction cache, prefetch few instructions
— 8088 (8 bit external bus) used in first IBM PC
• 80286
— 16 Mbyte memory addressable
— up from 1Mb
• 80386
— 32 bit
— Support for multitasking
Pentium Evolution (2)
• 80486
—sophisticated powerful cache and instruction
pipelining
—built in maths co-processor
• Pentium
—Superscalar
—Multiple instructions executed in parallel
• Pentium Pro
—Increased superscalar organization
—Aggressive register renaming
—branch prediction
—data flow analysis
—speculative execution
Pentium Evolution (3)
• Pentium II
—MMX technology
—graphics, video & audio processing
• Pentium III
—Additional floating point instructions for 3D graphics
• Pentium 4
—Further floating point and multimedia enhancements
• Duo, Quad, and 6 core Processors
—Similar design to P4, but more “processing units”.
• Itanium
—64 bit, see later lectures
• See Intel web pages for detailed information on
processors
PERFORMANCE
Computer Performance Measures
• Still have problems assessing differing
architectures
—How well (fast) will the machine work?
• Can view a machines performance in two
(competing) ways:
—Increase in overall throughput
—Increase in response time to an individual job
CPU performance
• Performance can be defined in Millions of
instructions per second (MIPS)
—Rarely used by modern processors as a benchmark
—Very popular with embedded processors
• Also can be measured in Millions of floating
point operations per second (MFLOPS)
—Common benchmark for modern processors
– Almost never used with embedded processors
+ Why?
• Does a faster clock cycle improve performance?
—Not always
Faster computers
• Improved Bus speed and Width
• Faster and/or more effective memory
—Move more data to and from CPU, minimize latency
and kept the CPU busy as much as possible.
• Assembly language/ machine code
—RISC vs CISC code
Other Considerations
• Cost
—Design
—purchase
—components
—Maintenance
• Compatibility and software availability
Q&A